I know they go for the 'sweet' nectar and that those feeders aren't their only source of food. I believe animals are smart enough to know what is good for them to consume and what is not. You could try putting other things in their water, but I guartantee they won't drink it if it's not what they need and want.
Other animals, like chickens and pigs and others, seem to consume just about anything!
In any case, God designed them perfectly and they are born with fully installed and functional software!